Abstract:
The sunlight-driven fixation of CO2 into valuable chemicals
constitutes a promising approach toward environmental remediation and energy
sustainability over traditional thermal-driven fixation. Consequently, in this article,
we report a strategic design and utilization of Mg-centered porphyrin-based metal−
organic framework (MOFs) having relevance to chlorophyll in green plants as a
visible light-promoted highly recyclable catalyst for the effective fixation of CO2 into
value-added cyclic carbonates under ambient conditions. Indeed, the Mg-centered
porphyrin MOF showed good CO2 capture ability with a high heat of adsorption
(44.5 kJ/mol) and superior catalytic activity under visible light irradiation in
comparison to thermal-driven conditions. The excellent light-promoted catalytic
activity of Mg−porphyrin MOF has been attributed to facile ligand-to-metal charge
transfer transition from the photoexcited Mg−porphyrin unit (SBU) to the Zr6
cluster which in turn activates CO2, thereby lowering the activation barrier for its
cycloaddition with epoxides. The in-depth theoretical studies further unveiled the detailed mechanistic path of the light-promoted
conversion of CO2 into high-value cyclic carbonates. This study represents a rare demonstration of sunlight-promoted sustainable
fixation of CO2, a greenhouse gas into value-added chemicals
